Centralized communication devices typically include baseband, radio modem, and radio front-end. The modem modulates and demodulates the carrier signals to encode and decode the transmitted and received information. The front-end includes a power amplifier to amplify the signal being transmitted, a low noise amplifier to amplify the received signals, a time or frequency duplexer, and an antenna to send and receive signals to/from external devices. In a centralized system, the radio modem and the radio front-end are physically together, often as a single integrated circuit chip or several chips fixed on circuit boards that cannot move against each other.
Many applications require flexibility in changing the position or orientation of antennas. However, in a centralized communication device, the positions are fixed on an integrated chip or a circuit board and there is no flexibility in changing the position. This limits the optimal positioning and orientation of the antenna, which in turn results in lower sensitivity and lower performance of the system.